Fuel injection apparatus for an internal combustion engine

ABSTRACT

An apparatus is provided for stopping fuel injection in a fuel injection type internal combustion engine wherein a fuel supply passage for a fuel injection pump incorporates a pusher facing an inlet valve of the pump. The pusher is arranged such that during ordinary engine operation, the pusher is retracted to an inoperative position by the supply pressure of the fuel within the fuel supply passage whereas a valve is displaced upon rapid reduction of engine speed to connect the fuel supply passage with the outside atmosphere.

[ June6,1972

IJite States Patet Yoshino M u m m m [54] FUEL INJECTION APP s; INTERNAL COMBUSTION ENGINE [72] Inventor:

Bartod 123/140 MP Hiroyuki Yoshino, Asaka, Japan Assignee: Honda Giken Kogyo Kabushiki Kaisha,

y Japan Primary Examiner-Laurence M. Goodridge Attorney-Waters, Roditi, Schwartz & Nissen [22] Filed: Oct. 14, 1970 [21] Appl. No.1

An apparatus is provided for stopping fuel injection in a fuel [30] Foreign Apphcauon Priority Data injection type internal combustion engine wherein a fuel May 21, 1970 Japan..11...1...,..................... .45/49O63 upp y passage for a fuel injection pump incorporates a pusher facing an inlet valve of the pump. The pusher is arranged such 3 mfmcm m me m bm fd .m sm .l ame h v S O u c v pr mpaww iwwdm e0. nP [6S o ePo wS S m m F em 8 anw e em S .m f mPm oo efll unm y Jm PD-{h a uc. n u .wld m eee a rg r a gw dS momma fntap .l T dnmnw m qmmw. lmwus WM w AU 2 9 M O 3F m 1 52 u.s.c1.....,...........123 140 MP, 123 97 B, 123/139 DE,

53 Field ofSearch.......123/139 P, 139 R, 139 AL, 139 AN, 123/139 AW, 139 B0, 140 MP, 140 MC; 417 253,

7 Claims, 1 Drawing Figure FUEL INJECTION APPARATUS FOR AN INTERNAL COMBUSTION ENGINE BRIEF SUMMARY OF THE INVENTION The invention relates to fuel injection apparatus for an internal combustion engine and more specifically to fuel injection apparatus in which fuel injection is immediately terminated when the engine speed is rapidly decreased, such decrease of engine speed being produced when the throttle valve is rapidly closed such as during an engine braking operation.

According to the invention the fuel injection apparatus comprises fuel injection pump means for the supply of fuel to the engine, a fuel passage connected to the pump means for supply of fuel thereto, an inlet valve controlling flow of fuel between said passage and said pump means, a fuel by-pass passage connected to the first said fuel passage, a control valve between said passages for controlling the communication therebetween, means for operating said control valve to open the same upon rapid reduction of engine speed and thereby provide intercommunication between said passage, and pusher means subjected to the pressure in said fuel passage and facing said inlet valve to open the same when the control valve is opened.

In further accordance with the invention the bypass passage is open to atmospheric pressure and said pusher means comprises a displaceable pusher member for contacting said inlet valve to open the same and a spring means acting on the pusher member to urge the same towards the inlet valve, said pusher member being displaced, by the pressure of the fuel in said first passage, away from the inlet valve against the action of said spring means. On the contrary when the engine speed is rapidly reduced the control valve is opened and the pressure in the fuel passage drop to atmospheric whereby the pusher member now displaces the inlet valve to opened position under the action of the spring means.

BRIEF DESCRIPTION OF THE DRAWING The sole FIGURE of the drawing diagrammatically shows partly in section fuel injection apparatus according to the invention.

DETAILED DESCRIPTION The drawing shows a fuel injection apparatus wherein fuel sent from a fuel tank 1 by a pump 2 is fed under pressure by an injection pump 3 to a nozzle 4 for discharge within a suction pipe near a combustion chamber, of an internal combustion engine. The invention contemplates stoppage of fuel injection without fail at the time of rapid reduction of speed to prevent discharge of unburned fuel and consequent air pollution.

It is usual with engines of this kind that when the throttle valve is rapidly closed, for instance, during an engine brake operation, the amount of suction air is rapidly decreased, however, the fuel supply under pressure by the injection pump 3 is not immediately stopped, so that there is brought about an incomplete combustion which causes air pollution. This is also not desirable from the view-point of brake effect and fuel economy.

According to the invention, a fuel supply passage 5 for injection pump 3 is provided with an inlet valve opening pusher 7 facing an inlet valve 6 of the pump 3, and the pusher 7 is so arranged that, during ordinary operation, the pusher is displaced to a retracted or inoperative position by the pressure within the fuel supply passage 5 against the action of a spring 8. An opening valve 9 is provided which is moved in conjuction with the rapid reduction of engine speed to cause the fuel supply passage 5 to communicate with the outside atmosphere.

The injection pump 3 is of the plunger type. Numeral 10 denotes a cylinder, numeral 11 denotes a plunger driven by rotation of a cam 12, numeral 13 denotes a plunger return spring, numeral 14 denotes a discharge valve in communication with nozzle 4, and numeral 15 denotes a pressure control valve provided within an excess fuel return passage 16 for obtaining a supply pressure within the supply passage 5.

The illustrated injection pump 3 is for an opposed two cylinder type engine. A by-pass passage 17 is provided for connection with the supply passage 5 to furnish communication with the return passage 16, and the valve 9 is positioned within the passage 17 at the connecting portion thereof with the supply passage 5 as illustrated. The rear surface of the inlet valve opening pusher 7 is open to the outside atmosphere and in the illustrated embodiment the rear portion of the pusher 7 is positioned in the passage 17. The mechanism for the relative movement of valve 9 in conjunction with engine speed is in the form of a diaphragm valve operable in responseto negative pressure produced within the suction pipe at the time of closing of the throttle valve. Numeral 18 denotes a negative pressure pipe which connects a chamber 20 behind a diaphragm 19 and the engine suction pipe. The mechanism for movement of valve 9 may be of various other constructions, such as an electromagnetic valve operable when full closure of the throttle valve is detected, or a valve mechanically coupled to the throttle valve for displacement in conformance with rotation of the throttle valve.. I

At the time of ordinary engine operation, the fuel passes through the passage 5 from the pump 2 to reach the inlet valve 6 under a supply pressure determined by the pressure control valve 15. The pressure of the fuel in passage 5 opens valve 6 (against the action of the valve spring) during the suction stroke of plunger 11 to admit fuel to cylinder 10. Then the fuel is subjected to higher pressure by the plunger 11 and is supplied under the higher pressure to the nozzle 4 for discharge therefrom. The adjustment of the amount of fuel injection is effected by changing the stroke of the plunger 11 and for this purpose cam 12 is of conical shape and is axially moved in relation to the opening and closing operation of the throttle valve. The excess fuel, that is, the fuel left over from that supplied to the nozzle 4 is returned to the tank 1 through the passage 16..

If the throttle valve is rapidly-closed for rapid reduction of speed, the fuel supply passage opening valve 9 is moved to open position immediately in conjunction therewith, so that the fuel supply passage 5 is placed in communication with the by-pass passage 17 and the return passage 16, whereby the pressure within the passage 5 becomes atmospheric. Accordingly, the pusher 7 which has been in a retracted position under the pressure of the supply during the period of engine ordinary operation is now no longer subject to the supply pressure and is advanced by the action of the spring 8, whereby the inlet valve 6 is forcibly pushed up to be opened. Consequently, since the inlet valve is opened, any fuel within the cylinder 10 is urged by plunger 11 into the passages 17, 16 (of no resistance) and hence the fuel is not discharged to the nozzle 4. Thus the fuel injection is immediately stopped. If the throttle valve is again opened for acceleration, the valve 9 is closed and the pressure within the supply passage 5 rises, so that the pusher 7 is retracted by this pressure and the inlet valve 6 returns to the ordinary operating condition. In this case, as the passage leading to the cylinder 10 and the discharge valve 14 has already been filled with fuel, the injection can be immediately resumed.

According to this invention, as described above, when an engine speed reduction operation is effected, the inlet valve 6 of the fuel injection pump 3 is held in an open position so that the pump action of plunger 11 to nozzle 4 cannot be effected and the fuel injection is immediately stopped. This is effective for reduction in the fuel consumption and in purification of the exhaust gas during speed reduction. At the time of re-acceleration, the inlet valve 6 returns immediately to operating position and fuel injection is again effected continuously. Thus, there is provided a means for stopping fuel injection which effectively operates in accordance with acceleration and reduction operations.

What is claimed is:

1. A fuel injection apparatus for an internal combustion engine comprising fuel injection pump means for the supply of fuel to the engine, a fuel passage connected to the pump means for supply of fuel thereto, an inlet valve controlling flow of fuel between said passage and said pump means, a fuel by-pass passage open to atmospheric pressure and connected to the first said fuel passage, a control valve between said passages for controlling the communication therebetween, means for operating said control valve to open the same upon rapid reduction of engine speed and thereby provide intercommunication between said passages, and pusher means facing said inlet valve to open the same when the control valve is opened, said pusher means comprising a displaceable pusher member for contacting said inlet valve to open the same, and a spring means acting on the pusher member to urge the same towards the inlet valve, said pusher member being displaceable, by the pressure of the fuel in said first passage, away from the inlet valve against the action of said spring means,

2. Fuel injection apparatus as claimed in claim 1 comprising a pump connected to said first passage to supply fuel under pressure thereto.

3. Fuel injection apparatus as claimed in claim 2 comprising a fuel tank and a return line connecting the by-pass passage to said fuel injection pump means comprises a cylinder for receiving fuel from said fuel passage, a reciprocable plunger in said cylinder, and no72le means connected to said cylinder for discharge of fuel under the pressure developed by said plunger.

7. Fuel injection apparatus as claimed in claim 6 wherein a plurality of fuel injection pump means and corresponding inlet valves are provided, said fuel passage, by-pass passage and control valve being common to the plurality of pump means and respective inlet valves. 

1. A fuel injection apparatus for an internal combustion engine comprising fuel injection pump means for the supply of fuel to the engine, a fuel passage connected to the pump means for supply of fuel thereto, an inlet valve controlling flow of fuel between said passage and said pump means, a fuel by-pass passage open to atmospheric pressure and connected to the first said fuel passage, a control valve between said passages for controlling the communication therebetween, means for operating said control valve to open the same upon rapid reduction of engine speed and thereby provide intercommunication between said passages, and pusher means facing said inlet valve to open the same when the control valve is opened, said pusher means comprising a displaceable pusher member for contacting said inlet valve to open the same, and a spring means acting on the pusher member to urge the same towards the inlet valve, said pusher member being displaceable, by the pressure of the fuel in said first passage, away from the inlet valve against the action of said spring means.
 2. Fuel injection apparatus as claimed in claim 1 comprising a pump connected to said first passage to supply fuel under pressure thereto.
 3. Fuel injection apparatus as claimed in claim 2 comprising a fuel tank and a return line connecting the by-pass passage to said fuel tank.
 4. Fuel injection apparatus as claimed in claim 1 wherein said means for operating said control valve comprises a diaphragm connected to said control valve, and a suction chamber behind said diaphragm and subjected to suction pressure in the engine.
 5. Fuel injection apparatus as claimed in claim 1 wherein said fuel passage and by-pass passage are parallel, a connecting passage being provided and joining the fuel passage and by-pass passage, said control valve being displaceable in said connecting passage.
 6. Fuel injection apparatus as claimed in claim 1 wherein said fuel injection pump means comprises a cylinder for receiving fuel from said fuel passage, a reciprocable plunger in said cylinder, and nozzle means connected to said cylinder for discharge of fuel under the pressure developed by said plunger.
 7. Fuel injection apparatus as claimed in claim 6 wherein a plurality of fuel injection pump means and corresponding inlet valves are provided, said fuel passage, by-pass passage and control valve being common to the plurality of pump means and respective inlet valves. 